1. Field of the Invention
The present invention relates to processes of preparing glycolurils and cucurbiturils using the glycolurils, and more particularly, to processes of preparing glycolurils and cucurbiturils using the glycolurils by microwave irradiation.
2. Description of the Related Art
Cucurbiturils were first reported by R. Behrend, E. Meyer, and F. Rusche in 1905 [Liebigs Ann. Chem. 1905, 1, 339]. According to their report, first, urea and glyoxal are stirred in the presence of hydrochloric acid (HCl) for two hours to produce glycolurils. The condensation of the glycolurils with excess formaldehyde in the presence of HCl produces an amorphous precipitate. Dissolution of the precipitate in hot concentrated sulfuric acid followed by dilution with water produces a crystalline material. In 1981, W. Mock and his coworkers characterized the crystalline material as a hexameric macrocyclic compound with the composition of C36H36N24O12 which was confirmed by X-ray crystal structure determination [J. Am. Chem. Soc. 1981, 103, 7367]. Since then, an improved synthetic method of cucurbit[6]uril has been disclosed (DE 196 03 377 A1). Further, a synthetic method for various cucurbituril homologues under low-temperature reaction conditions has been reported (U.S. Pat. No. 6,365,734). In addition, water-soluble and organic-soluble cucurbiturils and a preparation method thereof have been disclosed (PCT/KR02/01259). According to the preparation method disclosed in this patent application, first, a strong acid solution and glycolurils or their derivatives are added to formaldehyde and incubated at 70-100° C. for 20-40 hours. Then, the reaction solution is concentrated by heating and cooled to room temperature to produce cucurbituril derivatives. As described above, a condensation reaction involved in conventional synthesis of glycolurils and cucurbituril derivatives requires a high reaction temperature and a long reaction time.